Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH] [38/99] Fix oops caused by queue refcounting failure | Date | Wed, 27 Jul 2011 14:48:37 -0700 (PDT) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: James Bottomley <James.Bottomley@HansenPartnership.com>
commit e73e079bf128d68284efedeba1fbbc18d78610f9 upstream.
In certain circumstances, we can get an oops from a torn down device. Most notably this is from CD roms trying to call scsi_ioctl. The root cause of the problem is the fact that after scsi_remove_device() has been called, the queue is fully torn down. This is actually wrong since the queue can be used until the sdev release function is called. Therefore, we add an extra reference to the queue which is released in sdev->release, so the queue always exists.
Reported-by: Parag Warudkar <parag.lkml@gmail.com> Signed-off-by: James Bottomley <jbottomley@parallels.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Andi Kleen <ak@linux.intel.com>
--- drivers/scsi/scsi_scan.c | 2 +- drivers/scsi/scsi_sysfs.c | 1 + 2 files changed, 2 insertions(+), 1 deletion(-)
Index: linux-2.6.35.y/drivers/scsi/scsi_scan.c =================================================================== --- linux-2.6.35.y.orig/drivers/scsi/scsi_scan.c +++ linux-2.6.35.y/drivers/scsi/scsi_scan.c @@ -295,7 +295,7 @@ static struct scsi_device *scsi_alloc_sd kfree(sdev); goto out; } - + blk_get_queue(sdev->request_queue); sdev->request_queue->queuedata = sdev; scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun); Index: linux-2.6.35.y/drivers/scsi/scsi_sysfs.c =================================================================== --- linux-2.6.35.y.orig/drivers/scsi/scsi_sysfs.c +++ linux-2.6.35.y/drivers/scsi/scsi_sysfs.c @@ -319,6 +319,7 @@ static void scsi_device_dev_release_user kfree(evt); } + blk_put_queue(sdev->request_queue); /* NULL queue means the device can't be used */ sdev->request_queue = NULL;
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